CC-1065 is disclosed as an antibacterial and antineoplastic antibiotic in J. Antibiotics, 31 1211 (1978) and ibid, 34 1119 (1981); and USP 4169888. Further, duocarmycin A having a similar structure thereto and analogues thereof are disclosed in WO87/06265, EP0318056, J. Antibiotics 42 1229 (1989), and JP-A-4-99774.
Further derivatives of CC-1065 are disclosed in JP-A-60-193989, and Japan Patent Kohyo 2-502005. Derivatives of duocarmycins are disclosed in JP-A-3-7287, JP-A-3-128379, EP0354583, and EP0406749. All of these compounds are derived by utilizing the base skeleton of an unmodified natural substance or by modifying chemically a natural substance.
The clinical therapy of cancer includes surgical excision, X-ray radiotherapy, pharmacotherapy using a chemotherapeutic agent(chemotherapy), and so forth. Of these therapies, chemotherapy is the one and only therapy for cancer having wide-spread metastasis in several body regions and for cancer at the terminal stage. Originally, chemotherapy is expected to be the least to burden a patient, while in facts, chemotherapeutic agents hitherto known impose severe suffer on patients due to strong adverse reactions. Further, there are several effective chemotherapeutic agents against leukemia which grows rapidly, but most of them are less effective for solid tumor which grows slowly. From these reasons, chemotherapy so far is not always primarily adopted for cancer.
In view of the present status of the chemotherapeutic agents, the inventors of the present invention have conducted comprehensively the investigation on compounds which exhibit high selectivity to cancer cells and exhibit high efficacy also on solid tumor with less toxicity.